/i  /  7,  r  - '  / 


,1  25,  L90S 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

Bl  REAU  OF  PLANT  [NDUSTRY-Circular  Kq.  11. 
B.  T.  GALLOWAY,  Chief  of  Bureau. 


DANGER  IX  JUDGING  COTTON  VARIETIES 
BY  LINT  PERCENTAGES. 


O.   K.  (OOK. 

Bionomist  in  Charge  of  Bionomic  Investigations 

of  Tropical  and  Subtropical  Pj  w  rs. 


^  ^  **»» 

BUREAU  OF  PLANT  INDUSTRY. 

Physiologist  and  Pathologist,  and  Chief  of  Bureau,  Beverly  T.  Galloway. 

Physiologist  and  Pathologist,  and  Assistant  Chief  of  Bureau,  Albert  F.  Woods. 

Laboratory  of  Plant  Pathology,  Erwin  F.  Smith.  Pathologist  in  Charge. 

Investigations  of  Diseases  of  Fruits,  Morton  B.  Waite,  Pathologist  in  Charge. 

Laboratory  of  Forest  Pathology,  Haven  Metealf.  Pathologist  in  Charge. 

Cotton  and  Truck  Diseases  and  Plant  Disease  Survey,  William  A.  Orton,  Pathologist  in  Charge. 

Plant  Life  History  Investigations,  Walter  T.  Swingle,  Physiologist  in  Charge. 

Cotton  Breeding  Investigations,  Archibald  D.  Shamel  and  Daniel  N.  Shoemaker,  Physiologists  in  Charge. 

Tobacco  Investigations,  Archibald  D.  Shamel,  Wightman  W.  Garner,  and  Ernest  H.  Mathewson,  in 

Charge. 
Corn  Investigations,  Charles  P.  Hartley.  Physiologist  in  Charge. 

Alkali  and  Drought  Resistant  Plant  Breeding  Investigations,  Thomas  II.  Kearney,  Physiologist  in  Charge. 
Soil  Bacteriology  and  Water  Purification  Investigations,  Karl  F.  Kellerman,  Physiologist  in  Charge. 
Bionomic  Investigations  of  Tropical  and  Subtropical  Plants,  Orator  F.  Cook,  Bionomist  in  Charge. 
Drug  and  Poisonous  Plant  Investigations  and  Tea  Culture  Investigations,  Rodney  II.  True.  Physiologist 

in  Charge. 
Physical  Laboratory,  Lyman  J.  Briggs,  Physicist  in  Charge. 

Crop  Technology  and  Fiber  Plant  Investigations,  Nathan  A.  Cobb,  Crop  Technologist  in  Charge. 
Taxonomic  and  Range  Investigations,  Frederick  V.  Coville,  Botanist  in  Charge. 
Farm  Management  Investigations,  William  J.  Spillman,  Agriculturist  in  Charge. 
Grain  Investigations,  Mark  Alfred  Carleton.  Cerealist  in  Charge. 
Arlington  Experimental  Farm,  Lee  C.  Corbett,  Horticulturist  in  Charge. 
Vegetable  Testing  Gardens,  William  \V.  Tracy,  sr.,  Superintendent. 
Sugar-Beet  Investigations,  Charles  O.  Townsend,  Pathologist  in  Charge. 
Western  Agricultural  Extension  Investigations,  Carl  S.  Scofield,  Agriculturist  in  Charge. 
Dry-Land  Agriculture  Investigations,  E.  Channing  Chilcott,  Agriculturist  in  ('harp'. 
Pomological  Collections,  flustavus  B.  Brackett,  Pomologist  in  Charge. 

Field  Investigations  in  Pomology.  William  A.  Taylor  and  G.  Harold  Powell.  Pomologists  in  Charge. 
Experimi  ntal  Gardt  ns  and  Grounds.  Edward  M.  Byrnes.  Superintendent. 
Foreign  Seed  and  Plant  Introduction,  David  Fairchild,  Agricultural  Explorer  in  Charge. 
Forage  Crop  Investigations,  Charles  V.  Piper.  Agrostologist  in  Charge. 
Seed  Laboratory.  Edgar  Brown,  Botanist  in  Charge. 
Grain  Standardization.  John  D.  Shanahan,  Crop  Technologist  in  Charge. 
Subtropical  Laboratory  and  Garden.  Miami.  Fla..  Ernst  A.  Bessey,  Pathologist  in  Charge. 
Plant  Introduction  Garden,  Chico,  Cat,  \Y.  W.  Tracy,  jr..  Assistant  Botanist  in  Charge. 
South  Texas  Gardt  n.  Brcm  nsviUe,  Tex.,  Edward  ('.  Green.  Pomologist  in  Charge. 
Farmers'  Cooperative  Demonstration  Work,  Seaman  A.  Knapp,  Special  Agent  in  Chi 
Seed  Distribution  (directed  by  Chief  of  Bureau).  Lisle  Morrison.  Assistant  in  General  Charge. 


Editor.  J.  E.  Rockwell. 

[Cir.  11]  Chief  Clerk,  .lames  E.  Jones. 

2 


B.  I\  I.-3S4. 


DANGER    IN  JUDGING  COTTON  VARIETIES 
BY  LINT  PERCENTAGES. 


INTRODUCTION. 

Many  instances  mighl  be  collected  to  show  bow  injudicious  selec- 
tion can  work  injury  to  domesticated  varieties  of  animals  and 
plants.  Too  persistenl  attention  to  a  single  character  or  standard 
often  results  in  the  Qeglecl  of  other  indispensable  qualities  whose 
importance  may  remain  unconsidered  until  some  serious  deficiency 
is  revealed.  Thus  the  coffee  planter  who  selects  for  Large  seeds 
without  reference  to  other  characters  soon  finds  thai  be  lias  in- 
creased the  proportion  of  loose  and  irregular  "beans,"  for  these  are 
frequently  larger  than  any  of  the  normal  seeds. 

True  improvements  of  varieties  involve  the  preservation  of  high 
standards  in  manj  directions  at  once.  It  may  be  allowable  to  spe- 
cialize on  one  desirable  feature  or  another,  hut  none  of  the  essentials 
can  be  safelj  left  out  of  account.  The  use  of  lint  percentages  as  one 
of  the  primary  standards  in  the  selection  of  cotton  varieties,  and 
often  as  the  single  standard,  is  one  of  these  dangerous  tendencies 
which  is  likely  to  lead  to  injury  rather  than  to  improvement  if  cau- 
tion and  discrimination  are  not  learned  from  an  appreciation  of  other 
factors. 

The  danger  of  laying  too  much  emphasis  upon  the  percentage  of 
lint  is  greatly  increased  by  the  practice  common  in  some  parts  of  the 
-  it  1 1  of  selling  the  seed  cotton  on  the  basis  of  the  percentage  of  lint 
found  in  a  tested  sample  of  the  crop.  No  scientific  breeder  would 
hold  thai  selection  should  be  based  on  linl  percentages  alone,  hut  if 
the  lint  percentage  continues  to  appeal-  as  the  chief  issue  in  the 
mind-  of  the  farmer  and  of  the  commercial  seed  dealer  much  unin- 
tentional damage  may  be  done.  Inferior  and  unproductive  varieties 
are  likely  to  be  planted  if  they  have  high  percentages  and  actually 
superior  varieties  refused  merel}  because  their  percentages  arc 
lower.     Thus  it  has  hern  reported  h\   Mr.  William  A.  Orton  thai  an 

r.  11]  3 


4  JUDGING    COTTOK    VARIETIES   BY   LINT    PERCENTAGES. 

improved  variety  of  Sea  Island  cotton  Rivers  .  specially  selected  and 
distributed  by  the  Bureau  of  Plant  Industry  of  the  United  States 
Department  of  Agriculture,  has  failed  to  become  popular  because  the 
lint  percentage  is  slightly  lower  than  in  some  other  varieties,  though 
in  actual  yield  of  lint  it  "compares  favorably  with  any  other."" 

It  would  be  a  serious  misfortune  if  the  buying  and  selling  of  un- 
ginned  cotton  on  the  basis  of  lint  percentage  should  be  the  cause  of 
extending  this  mistaken  idea  that  lint  percentage  is  all-important. 
Some  of  the  State:-  prohibit  the  sale  of  unginned  cotton  as  a  means 
of  protecting  farmers  against  thieves,  hut  the  method  of  buying  by 
lint  percentage  is  in  itself  neither  unjust  nor  inconvenient.  It  is 
essential,  however,  that  the  farmer,  as  well  as  the  seedsman  and  the 
breeder,  shall  understand  that  lint  percentages  are  being  connected 
with  two  entirely  separate  problems.  The  use  of  the  lint  percentage 
to  figure  out  the  value  of  the  commodity  has  nothing  to  do  with  the 
way  the  lint  percentage  should  he  used  in  determining  the  value  of 
a  variety.  After  the  crop  is  ripe  and  the  price  is  agreed  upon  the 
percentage  of  lint  determine-  what  the  farmer's  returns  shall  be. 
This  is  the  commercial  problem.  The  agricultural  problem  comes 
before  the  crop  is  planted.  It  is  to  choose  the  variety  which  will 
give  the  most  valuable  product.  Here  the  lint  percentage  is  only 
one  of  several  factors,  for  the  highest  percentage  of  lint  does  not 
insure  the  largest  or  the  most  valuable  crop. 

The  need  of  improving  cotton  varieties  and  method-  of  culture  is 
appreciated  now  as  never  before,  with  the  high  prices  of  the  fiber 
and  the  difficulty  of  securing  labor  to  produce  it.  Planter  and 
buyer  alike  are  interested  in  improving  the  quality  and  increasing 
the  yields.  The  time  must  soon  come  when  intelligent  farmers  will 
carefully  -elect  their  own  seed,  for  experiment-  are  showing  that 
larger  yields  and  better  staple  can  generally  he  secured  in  this  way 
than  by  the  frequent  change  of  varieties,  however  promising  the  new 
stocks  may  have  appeared  in  the  place  where  they  were  bred.  This 
makes  it  all  the  more  important  that  farmers  should  not  imagine  that 
attention  to  lint  percentages  alone  affords  any  assurance  that  a 
variety  is  being  improved  or  that  a  new  sort  is  superior  to  the  best 
that  their  own  neighborhood  affords. 

The  local  adjustment  of  cotton  varieties  is  a  matter*  of  much 
greater  practical  importance  than  is  generally  supposed.  Different 
conditions  result  in  notable  changes  in  the  behavior  of  the  plants. 
Even  a  superior  variety  may  show  a  serious  deterioration  when 
planted  for  the  first  time  in  a  new  place.  Improvements  in  yield 
ranging  between  10  and  20  per  cent  have  been  found  in  the  second 


•  on,  \Y.  A.     Sea  Island  Cotton,   Fanners'   Bulletin  302,   I  .  S,   Dept.  of  Agri- 
culture, p.  46.     1907. 

it] 


DGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES.  .> 

generation    over    the    adjacent    rows    representing    the    same    stock 
planted  in  the  Dew  place  for  the  (irsl  time. 

The  invasion  of  the  boll  weevil  is  leading  to  many  changes  in  the 
methods  of  culture  of  cotton,  and  corresponding  modifications  <>(  the 
standards  of  breeding  arc  also  required.  It  is  therefore  especially 
important  at  this  time  to  consider  all  the  factors  thai  bear  upon  the 
quest  ion  of  improvement. 

SMALLER  OR  LIGHTER   SEEDS  RAISE   LINT  PERCENTAGE. 

In  using  lint  percentages  for  commercial  purposes  the  size  of  the 
seed  does  Dot  need  to  be  considered,  for  the  object  is  merely  to  calcu- 
late the  amount  of  lint  in  a  given  quantity  of  seed  cotton.  When 
the  lint  percentage  is  u>n\  agriculturally  as  a  basis  for  estimating  the 
productiveness  of  a    variety   the  size  of  the  seed   must   he  taken   into 

ount,  for  the  vaiuc  percentage  with  a  large  seed  means  more  fiber 
for  the  same  number  of  seeds. 

If  all  (  otton  plants  produced  an  equal  Dumber  of  seeds  of  the  same 
size  and  weight  the  percentage  of  lint  would  be  an  index  of  the 
productiveness  of  a  variety,  but  it  is  not  safe  to  rely  upon  any  sueh 
assumed  equality,  for  the  numbers,  sizes,  and  weights  of  seeds  are 
extremel)  variable  factors  which  change  the  significance  of  tin-  per- 
centage. High  percentages  may  accompany  low  yields  or  may 
result    from  small  seeds. 

Smaller  or  lighter  seeds  increase  the  percentage  of  lint  quite  as 
effectively  a-  an  additional  amount  of  fiber.  Larger  seeds,  on  the 
contrary,  reduce  the  percentage  of  lint  in  spite  of  the  fad  that  the 
actual  amount  of  lint  in  the  boll  may  not  he  reduced.  Reduction  of 
the  size  of  the  seed  raises  the  percentage  of  lint  even  though  the 
libers  do  not  become  any  longer  and  are  not  set  an\  closer  together. 
'The  area  of  the  surface  of  the  seed  does  not  decline  as  rapidly  as  the 
weight  of  the  seed.  The  surface  is  reduced  in  proportion  to  the 
square  root  of  the  diameter,  the  weight  in  proportion  to  the  cube 
root . 

To  increase  the  lint-bearing  surface  of  a  cotton  seed  by  3  per  cent 
would  involve  an  increase  in  weight  of  about  30  percent.  The  per- 
centage of  increase  of  weight  in  the  snu\  altogether  outruns  the 
increase  in  percentage  of  lint,  and  makes  the  iwrcentagi  of  lim 
smaller  in  spite  of  an  increase  in  the  amount  of  lint.  Thus,  if  in  a 
variety  having  :!•'!  per  cent  of  lint  the  weighl  of  the  seed  were  in- 
creased by  one-third  the  lint  percentage  would  fall  to  about  26, 
even  though  the  amount  of  lint  were  increased  by  ;!  per  cent,  to  cor- 
respond with  the  larger  surface. 

Instances  where  the  lint  percentages  show  a  notable  decrease  in 
spite  ol  actual  additions  to  (he  amount  of  lint  are  very  common  in 
in 


6  JUDGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES. 

hybrids  between  cottons  of  the  Sea  Island  type  and  some  of  the 
Mexican  and  Central  American  representatives  of  the  Upland  series. 
A  Mexican  cotton  with  27  per  cent  of  lint  hybridized  by  Egyptian 
cotton  having  a  somewhat  higher  percentage  gave  a  progen}-  with  a 
percentage  of  only  22.9,  although  the  lint  increased  in  weight  from 
4.05  grams  to  4.45  grams  per  hundred  seeds.  This  addition  to  the 
lint  was  greatly  outweighed,  however,  by  the  enlargement  of  the 
seeds  from  10.95  to  14.75  grams  per  hundred.  To  make  sure  that  a 
higher  lint  percentage  is  accompanied  by  an  increased  amount  of 
lint  it  is  necessary  to  know  that  the  weight  of  the  seeds  has  not 
declined,  either  by  reduction  in  size  or  by  change  of  texture  or 
compactness. 

ADVANTAGE  OF  LARGE  SEEDS  AND  LARGE-SEEDED  VARIETIES. 

The  size  of  the  seed  is  a  question  of  practical  importance  apart  from 
the  question  of  lint.  In  former  decades  small  seeds  would  have 
appeared  preferable,  at  least  as  a  means  of  reducing  the  expense  of 
picking  and  handling.  The  increasing  demand  for  cotton  seed  for 
oil  and  other  uses  tends  to  reduce  this  preference  for  small  seeds. 
During  the  last  season  cotton  seed  was  nearly  worth  the  picking,  even 
without  the  lint.  The  prices  of  cotton  seed  need  not  go  much  higher 
before  large-seeded  varieties  will  be  directly  preferred. 

The  presence  of  the  boll  weevil  gives  large  seeds  a  definite  advan- 
tage, since  they  contribute  to  the  prompt  development  of  the  cotton 
by  giving  the  young  plant  a  better  start.  The  stronger  the  young 
plant  is  at  the  time  of  germination  the  greater  are  its  chances  of 
breaking  through  the  crust  of  sun-baked  earth  which  weak  seedlings 
are  often  unable  to  penetrate.  Small-seeded  varieties,  like  the  Peter- 
kin,  sometimes  fail  to  come  up,  while  large-seeded  types,  like  the 
Russell,  may  show  a  good  stand  under  the  same  conditions.  An 
instance  is  related  by  Mr.  L.  H.  Dewey,  of  the  Bureau  of  Plant  Indus- 
try, of  a  planter  who  selected  his  cotton  for  high  lint  percentage  and 
small  seed  until  the  seedlings  were  too  weak  to  come  up. 

After  germination  the  ability  of  the  young  seedlings  to  make  con- 
tinuous growth  must  still  depend  considerably  upon  their  size  and  the 
amount  of  stored  nutriment  contained  in  their  tissues.  The  faster 
they  grow  at  first  the  farther  their  roots  will  reach  down  into  the 
moist  soil  and  the  less  becomes  the  danger  of  being  dried  up  or  broken 
down  by  the  wind.  The  more  vigorous  the  seedlings  the  earlier  the 
varieties  should  be,  if  other  things  are  equal. 

Some  of  the  early  varieties,  like  the  King,  have  small  seeds,  as  they 
also  have  small  bolls  and  short  lint.  The  planting  of  such  varieties 
has  been  advocated  in  boll  weevil  districts  as  a  means  of  securing 
early  crops.  Nevertheless,  it  has  to  be  considered  that  this  form  of 
earliness,  secured  by  reducing  the  size  and  thus  shortening  the  period 

[Cir.  11J 


JUDGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES.  i 

of  development,  ma\  afford  no  better  protection  against  the  weevils 
than  can  be  obtained  in  some  of  the  large-seeded  big-boll  varieties. 

Earh  opening  of  the  bolls  i-  nol  the  best  index  of  the  amount  of 
protection  obtained  l>\  early  development.  Long  before  the  bolls 
are  mature  thej  are  beyond  the  reach  of  weevil  injury.  A  variety 
which  sets  a  crop  of  bolls  early  and  carries  them  past  the  danger  of 
weevil  infection  may  produce  a  larger  crop  in  the  presence  of  the 
weevils  than  the  variety  which  ripens  the  first  bolls.  Some  of  the 
Central  American  varieties  of  cotton  retain  the  mature  bolls  for  lon<_r 
periods  and  do  not  open  them  until  dry  weather  comes.  The  ideal 
babit  of  earliness  would  he  met  1>\  a  variety  which  could  develop  a 
large  Dumber  of  bolls  pasl  the  point  of  weevil  injury  earbj  in  the  -en- 
son.  Delay  in  the  date  of  opening  might  he  an  advantage  if  all  the 
hull-  would  open  together  and  thus  avoid  the  need  of  making  several 
pickings  <>(  t he  same  field. 

'Phi-  plan  of  developing  weevil  resistance  in  big-boll  cottons  is 
worth}  of  careful  consideration  for  the  further  reason  that  it  avoids 
the  injury  to  the  industry  which  i-  involved  in  extending  the  cultiva- 
tion of  the  small-seeded,  short-staple  varieties  on  the  ground  of  earli- 
ness. Misapprehension  regarding  the  importance  of  lint  percentages 
tend-  to  conceal  the  true  value  of  desirable  big-boll  varieties,  both 
those  now  known  in  Texas  and  the  other  more  definitely  weevil- 
resistanl  types  now  being  introduced  and  acclimatized  from  Mexico 
and  Central  America.  The  big-boll  varieties  also  have  large  seeds, 
so  that  the  lint  percentages  do  not  represent  their  true  value  in  com- 
parison with  small-seeded  varieties.  This  should  not  he  taken  to 
mean  that  the  big-boll  varieties  have  lower  percentages  than  other 
type-.  h>r  both  the  Texan  ami  the  Central  American  big-boll  types 
often  -linu  very  high  percentages.  The  point  is  that  a  high  per- 
centage in  a  large-seeded  big-boll  cotton  should  mean  more,  even  as  a 
percentage,  than  in  a  small-seeded  small-boiled  variety.  For  the 
reasons  already  indicated,  the  lint  has  to  he  relatively  more  abundant 
in  a  large-seeded  variety  to  indicate  even  the  same  percentage  as  in  a 
small-seeded  variety. 

Thus  it  appear-  that  too  much  reliance  upon  lint  percentages  as  a 
standard  for  judging  varieties  ha-  t  em  led  to  keep  us  from  fully  appre- 
ciating the  value  of  the  big-boll  varieties.  In  Texas,  at  least,  the 
inadequate  supply  of  labor  make-  the  large  bolls  a  very  desirable 
feat  ure.  for  t  he  cot  ton  can  be  picked  much  more  readily  and  cheaply. 
Picker-  are  often  willing  to  gather  big-boll  cotton  at  a  lower  price 
than  the  small-boll  varieties,  for  the  difference  in  the  size  of  the  bolls 
make-  considerable  difference  in  the  proceed-  of  a  daj  '-  labor.  When 
labor  is  scarce  the  farmers  who  are  unwilling  to  pay  a  higher  price  for 
picking  small-boll  varieties  sometime-  leave  their  cotton  unfathered 
in  the  fields. 

[CIr.   11] 


8  JUDGING    COTTON    VARIETIES   BY   LINT    PERCENTAGES. 

ADVANTAGES  OF  HEAVY   SEEDS. 

That  cotton  is  no  exception  to  other  crops  in  the  superiority  of 
firm,  heavy  seeds  has  been  demonstrated  b}7-  a  series  of  experiments 
made  by  Dr.  II.  J.  Webber  and  Mr.  E.  B.  Boykin,  of  the  Bureau  of 
Plant  Industry,  in  South  Carolina.  The  heavy  seeds  planted  sepa- 
rately gave  crops  about  10  per  cent  greater  than  the  light  seeds.  In 
Upland  cotton  the  fuzz  interferes  with  the  separation  of  the  light  and 
heavy  seed  b}r  winnowing,  but  it  was  found  that  this  could  be  obvi- 
ated by  rolling  the  seeds  in  a  revolving  drum  with  small  quantities 
of  paste,  to  stick  the  fuzz  together  and  render  the  seeds  easily  sepa- 
rable.0 

Deterioration  in  the  texture,  weight,  and  vitality  of  the  seeds  is 
one  of  the  frequent  symptoms  of  degeneracy  in  plants.  The  seeds 
are  the  young  plants  themselves.  By  weighing  and  other  tests  of 
the  seeds  we  can  learn  in  advance  whether  the  inclosed  plants  are 
healthy  and  vigorous  or  malformed  and  puny.  The  vigor  of  the  seed 
is  of  much  more  importance  in  afield  crop  than  in  garden  plants  which 
can  be  given  special  protection  in  their  earlier  stages.  The  seeds  of 
cotton  plants  in  particular  are  unusually  subject  to  injury  and  deterio- 
ration, and  the  young  seedlings  are  very  delicate,  as  the  farmer  learns 
from  the  frequent  need  of  replanting.  The  seed  coats  are  not  very 
strong.  As  in  many  other  tropical  plants  the  embryo  of  cotton  is 
very  large  and  is  only  loosely  rolled  up,  quite  unlike  the  seeds  of  mosi 
of  the  species  native  in  the  Temperate  Zone.  Unless  the  seed  is 
sheltered  and  kept  dry  freezing  readily  kills  it. 

HIGHER  LINT  PERCENTAGES  WITH  DIMINISHED  FERTILITY. 

If  two  cotton  plants  bear  the  same  number  of  bolls  containing  the 
same  number  of  seeds,  the  plant  with  the  higher  percentage  of  lint 
might  still  produce  less  cotton  than  the  other.  The  lint  percentage 
does  not  express  an  absolute  fact,  but  shows  only  a  relation  between 
the  lint  and  the  seed  which  may  or  may  not  be  an  indication  of 
greater  fertility.  Even  though  the  seeds  were  large  and  the  lint  per- 
centage still  remained  high,  the  number  of  bolls  might  be  reduced 
and  thus  counteract  the  advantage  of  the  increased  amount  of  lint  on 
the  individual  seeds.  Lint  percentages  can  not  be  substituted  for 
actual  tests  of  yield. 

When  the  productiveness  of  a  variety  or  strain  of  cotton  has  been 
fairly  and  thoroughly  tested,  these  results  must  replace  any  opini  ns 
that  may  have  been  formed  from  lint  percentages.  There  is  no  virtue 
at  all  in  lint  percentage  standing  alone.  Attention  to  lint  percent:  es 
serves  only  to  avoid  one  form  of  deterioration,  as  a  partial  substitute 

a  Webber,  II.  .1..  and  Boykin,  E.  B.     The  Advantages  of  Planting  Heavy  Cotton 
I,  Farmers'  Bulletin  285,  U.  S.  Depa  of  Agriculture.     1907. 

[Cir.   11  I 


JUDGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES.  9 

for  tests  nf  yield,  and  even  then  they  may  be  misleading  unless  the 
weight  of  the  seed  is  also  taken  into  account. 

To  secure  higher  percentages  of  lint  on  seeds  of  the  same  size  and 
weight  means  thai  the  fibers  have  to  be  longer,  or  coarser,  or  closer 
together.  Experiments  have  shown  thai  longer  lint  means,  almosl 
invariably,  reduced  percentages.  Coarser  lint  is  not  desired,  so  that 
the  crowding  of  the  lint  closer  together  would  he  the  real  objecl  of 
selection  for  higher  percentages.  But  whatever  the  character  upon 
which  selections  are  based,  narrow  breeding  to  secure  very  high 
degrees  of  expression  of  particular  characters  carries  with  it  the 
genera]  result  of  diminished  fertility. 

To  reduce  the  fertility  of  a  variety  l>\  careful  selection  for  high  per- 
centages would  he  in  accord  with  the  usual  result  of  diminished  fer- 
tility in  highlj  specialized,  narrowly  selected  types.  Selection  by  lint 
ntages  instead  of  increasing  the  agricultural  value  of  a  variety 
might  actually  diminish  it.  The  value  of  the  variety  mighl  go  stead- 
ily downward  while  the  lint  percentage  was  advancing.  Thus,  higher 
percentages  of  lint  are  not  only  unreliable  as  indications  of  increased 
production  bul  aught  even  accompany  declining  yields  in  degener- 
ating variel  ies. 

If  the  -election  began  with  a  variety  having  a  tendency  to  larger 
amounts  of  lint,  selection  might  he  followed  by  a  further  increase  of 
the  character,  hut  a  careful  and  persistent  selection  might  he  expected 
to  bring  the  other  factor-  of  small  or  light  srvA  and  reduced  fertility 
into  operation.  Domesticated  varieties  usually  degenerate  much 
more  readily  than  they  advance  to  higher  standards.  To  specialize 
our  varieties  of  held  crops  in  characters  which  have  no  practical 
importance  i-  not  only  a  waste  of  effort  but  may  actually  injure  them. 

LARGE  YIELDS  WITHOUT  HIGH  PERCENTAGES. 

It  mighl  lie  argued  thai  plant-  could  produce  more  seed-  if  the  seeds 
were  smaller  and  that  more  lint  could  he  secured  from  varieties  with 
smaller  seeds  and  higher  percentages.  It  is  true  that  the  same 
amount  of  seed  material  made  up  into  small  seeds  would  produce 
more  lint-bearing  surface  than  if  made  up  into  larger  seeds,  h 
does  not  follow,  however,  that  this  method  of  increasing  the  lint 
accord-  with  the  physiological  economy  of  the  plant.  A-  vet  we 
have  no  evidence  that  varieties  can  lie  improved  in  yield  by  reducing 
the  -ceils  and  thus  securing  the  higher  percentages  that  result  from 
the  smaller  -i/.e. 

That  there  is  no  necessary  connection  between  lint  percentages 
and  yields  is  shown  by  the  fact  that  very  high  yields  are  obtain  d 
from  varieties  with  relatively  low  percentages  of  lint.  In  Sea  Island 
ami  Egyptian  cottons  the  percentages  fall  below  those  reached  in 
some  of  our  Upland  varieties,  hut   huh  yields  are  not   prevented  l>v 

[Cir.   11] 


10  JUDGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES. 

lower  percentages  of  lint.  It  is  well  known  that  the  yields  of  cotton 
obtained  in  Egypt  range  distinctly  higher  than  in  the  United  States. 

Similar  results  have  now  been  obtained  in  experiments  with  Egyp- 
tian cotton  in  the  United  States  conducted  by  Mr.  T.  H.  Kearney, 
of  the  Bureau  of  Plant  Industry.  After  several  years  of  acclimati- 
zation and  selection  at  Yuma,  Ariz.,  the  Egyptian  cotton  is  showing 
its  normal  fertility.  It  yielded  in  1907  at  the  rate  of  3,330  pounds 
of  seed  cotton  per  acre,  more  than  any  of  the  Upland  varieties  in- 
cluded in  the  test.  The  yield  of  lint  was  slightly  exceeded  by  one 
of  the  Upland  varieties,  but  the  value  of  the  lint  of  the  Egyptian 
cotton  was  much  greater  than  that  of  the  Upland. 

The  results  of  many  tests  of  Upland  varieties  at  the  experiment 
stations  of  several  of  the  Southern  States  have  been  tabulated  by 
Mr.  Fred.  J.  Tyler,  of  the  Bureau  of  Plant  Industry,  who  finds  that 
the  highest  yields  are  secured  from  varieties  with  the  higher  per- 
centages of  lint,  as  might  be  expected  from  the  fact  that  the  improved 
varieties  have  generally  been  selected  with  reference  to  the  per- 
centage of  lint.  At  the  same  time  it  is  evident  from  the  figures  that 
there  is  no  very  direct  or  necessary  relation  between  lint  percentage 
and  yield,  for  some  of  the  notably  prolific  varieties  show  only  mod- 
erately high  percentages  of  lint.  Thus,  the  Russell  variety  has  an 
excellent  reputation  as  a  yielder  of  large  crops  of  lint,  though  its 
percentage  is  only  32. 

Another  even  more  striking  instance  has  come  to  light  in  a  recently 
published  report  of  the  Department  of  Agriculture  of  North  Carolina. 
The  results  of  tests  of  27  varieties  are  tabulated  separately  with  refer- 
ence to  several  different  factors.  The  variety  which  gave  the  best 
returns  for  the  farmer  and  was  first  in  actual  amount  of  lint  stood 
as  No.  13  in  percentage  of  lint.  The  variety  with  the  highest 
percentage  of  lint  stood  as  No.  20  in  yield  of  lint  and  in  agri- 
cultural value.  The  high  percentage  of  lint  was  not  connected  with 
greater  fertility,  but  was  evidently  a  consequence  of  the  small  size 
of  seeds.  The  variety  which  produced  the  most  lint  ranked  as 
No.  3  in  size  of  seeds,  while  the  variety  with  the  highest  lint  percent- 
age fell  to  No.  23  in  size  of  seed;  finally,  it  was  the  latest  in  ripening 
of  the  whole  series  of  varieties." 

Other  things  being  equal,  the  high-percentage  varieties  would 
always  yield  more  lint,  hut  it  is  evident  that  the  other  things  are 
often  unequal  and  that  the  high  percentages  have  no  fixed  connec- 
tion with  vigor  and  fertility.  Tint  percentage  is  important  as  long 
as  the  other  features  are  not  left  out  of  account,  hut  persistent  selec- 
tion for  lint  percentage  alone  would  he  as  likely  to  reduce  the  crop 
as  to  increase  it. 

a  Bulletin  of  the  North  Carolina  Department  of  Agriculture,  vol.  29,  No.  -.  p.  IT. 
February,  L908. 
[Cir.  n  1 


JUDGING  COTTON    VARIETIES   B^     l.i.\i     PERCENTAGES.  11 

HIGH  QUALITY  WITH  LOW  PERCENTAGES. 

If  high-linl  percentages  do  Dot  insure  high  yields,  much  less  do 
the)  insure  high  quality.  With  longer  lint  the  percentage  might 
be  expected  to  rise,  but  the  change  is  almost  invariably  in  the  oppo- 
site direction.  In  spite  of  the  greater  length,  the  percentage  falls 
rapidbj   as  the  lint  of  carefully  selected  varieties  becomes  longer. 

Longer  lint,  even  in  Upland  varieties,  is  usually  accompanied  by 
ii  deficiency  of  fuzz,  as  though  the  long  lint  were  being  attained  by 
an  approach  to  the  characters  of  the  Sea  [sland  and  Egyptian  types, 
where  the  seeds  are  lefl  smooth  and  naked  after  the  lint  is  removed. 
As  the  In/./,  is  weighed  with  the  seed  the  absence  of  fuzz  reduces  the 
weight  of  the  seed  and  tends  to  increase  the  percentage  of  lint. 
Nevertheless,  the  rule  is  that  the  lint  percentage  declines  with  even 
increase  in  the  length  of  lint  and  smoothness  of  seed. 

Differences  in  the  size-  of  the  seeds  would  affect  these  results  and 
would  have  to  he  taken  into  account  in  an\  efforl  t"  determine  the 
true  relation  of  the  reduced  percentage  to  the  actual  yield  of  lint. 
If  the  seeds  were  becoming  larger,  the  reduced  percentage  of  lint 
might  not  involve  a  reduction  in  yield,  while  if  the  seeds  were  be- 
coming smaller,  the  yield  might  decline  even  more  rapidly  than  the 
percentage  would  indicate. 

Very  high  quality  and  very  high  percentages  being  apparently 
incompatible  characters,  the  raising  of  percentages  must  he  recog- 
nized a-  a  secondary  consideration  when  high  quality  is  seriously 
desired.  With  sufficient  differences  in  price,  low  percentages  of  lint, 
even  if  they  involve  smaller  crops,  may  still  leave  an  advantage 
for  the  farmer.  High  grades  of  cotton  are  more  than  ever  in  demand. 
The  time  must  soon  conic  when  the  question  of  quality  will  secure 
more  careful  consideration  in  all  parts  of  the  cotton  belt. 

It  is  true  that  there  are  still  many  districts  where  the  individual 
farmer  can  secure  little  or  no  advantage  from  improving  the  quality 
of  hi-  crop.  'The  local  buyer  may  refuse  to  pa\  a  higher  price  1" 
individual  farmer-  who  gro'w  better  staple-,  especially  if  only  a  few 
hale-  are  to  he  hail  and  the  locality  i-  not  known  in  the  trade  as 
producing  a  superior  quality  of  cotton.  Conceited  action  in  a 
whole  community  or  district  is  a-  important  in  the  choice  of  varieties 
a-  in  the  application  of  measures  of  protection  againsl  the  boll  weevil, 
[f  -Mine  of  the  farmers  carelessly  continue  the  planting  of  inferior 
varieties'  the  whole  district  suffers,  just  as  careless  farmer-  may 
keep  their  neighbors  supplied  with  boll  weevils  instead  of  contrib- 
uting an  honest  -hare  of  effort  toward  mitigating  the  pest.  A.sso 
ciations  of  cotton  planter-  are  giving  such  matter-  their  attention, 
the  importance  of  concerted  action  being  more  and  more  appreciated. 
m 


12  JUDGING   COTTON    VARIETIES   BY   LINT   PERCENTAGES. 

TRUE    STANDARD  OF  YIELD  IN  COTTON. 

The  fact  which  would  give  the  mosl  direct  indication  of  pro- 
ductiveness is  not  the  proportion  between  the  lint  and  the  seed,  but 
the  proportion  of  the  lint  to  the  plant  as  a  whole.  Comparison 
of  the  weight  of  the  lint  with  the  weight  of  the  plant  would  deter- 
mine how  much  in  the  way  of  other  tissues  the  plant  has  formed  in 
producing  a  given  amount  of  lint.  It  shows  how  efficient  the  plant 
is  in  producing  lint.  Such  percentages  of  lint  to  dry  weight  of  whole 
plants  are  not  always  easy  to  secure,  because  many  of  the  leaves  may 
fall  before  all  of  the  bolls  are  mature.  Even  without  weighing  the 
plants  itispossible  by  mere  inspection  in  t  lie  held  to  judge  something 
of  their  productive  efficiency. 

The  total  yield  of  the  individual  plant  is  not  a  completely  satis- 
factory index  of  the  productiveness  of  the  variety  under  field  con- 
ditions if  the  plants  are  disproportionately  large.  The  yield  per 
acre  may  not  be  increased  by  larger  individual  production  if  the  num- 
ber of  plants  is  reduced.  No  method  of  judging  individual  plants 
can  be  accepted  as  a  complete  substitute  lor  actual  held  tests. 

There  should  he  no  discrimination  against  small  plants  if  they  are 
fertile  in  proportion  to  their  size.  If  plants  are  small  they  can  grow- 
closer  together.  Small  plants  have  a  distinct  advantage  in  weevil 
resistance,  for  they  can  mature  a  larger  proportion  of  the  crop  early 
iu  the  season,  before  the  weevils  become  sufficiently  numerous  to 
prevent  the  development  of  the  buds  and  bolls. 

Prompt  production  often  has  another  advantage  in  the  drier 
regions  of  the  Southwestern  States,  where  cotton  cultivation  is  now 
making  rapid  advances,  partly  because  of  the  prevailing  high  prices 
of  cotton  and  partly  because  the  holl  weevil  does  less  damage  than 
in  the  humid  regions  nearer  to  the  Gulf  of  Mexico.  A  small  early 
type  of  cotton  may  he  able  to  make  prompt  use  of  the  available 
supply  of  water  in  the  soil  and  thus  mature  a  crop,  whereas  a  large 
late  variety  may  fail  through  drought  to  reach  a  productive  maturity. 

A  LINT  INDEX  FOR  JUDGING  VARIETIES. 

Since  the  lint  percentage  alone  is  not  a  suitable  standard  forjudg- 
ing varieties,  the  question  nat  u rally  arises  whether  any  other  standard 
would  better  serve  the  purposes  for  which  the  lint  percentage  is  now- 
employed.  In  the  work  of  securing  improved  strains  of  cotton  by 
selection  it  is  very  important  that  tin-  breeder  have  as  good  a  means 
as  possible  of  judging  in  advance  whether  the  plants  that  appear 
desirable  in  other  respects  can  also  he  expected  to  excel  in  pro- 
duct iveness. 

It  is  commonly  recognized  that  the  yields  of  individual  plants, 
single  rows,  or  small  plots  arc  not  t  rustworthy  indications  of  out-turn 

[Cir.   11  I 


DGING    COTTON    VARIETIES    BY    LINT    PERCENTAGES.  1  'A 

in  the  field,  and  it  is  often  supposed  thai  the  lint  percentage  repre- 
sents something  more  definite  and  reliable.  [laving  recognized  the 
er  that  high  lint  percentages  arc  likely  to  be  accompanied  by 
small  seeds  and  small  bolls,  we  must  seek  the  most  practicable  means 
iif  avoiding  these  dangers  b)  basing  our  judgment  on  some  [ess 
equivocal  standard.  Though  nothing  short  of  actual  Held  tests 
will  determine  the  productiveness  of  a  variety  and  its  adaptation  to 
local  conditions,  it  is  entirely  possible  to  avoid  some  of  the  uncertain- 
of  lint  percentages  by  using  as  a  lint  index  the  weight  of  the  lint 
itself  instead  of  the  less  important  proportion  between  the  lint  and 
the  seeds. 

The  lint  from  100  seeds  of  Upland  cottons  ranges  in  weight  from  t> 
grams  or  [ess  to  9  grams  and  upw  ard,  ami  t  hese  figures  can  be  directly 
applied  as  a  standard  in  judging  varieties  in  place  of  the  lint  per 
centages.  A  lint  index  on  this  basis  would  mean  something  actually 
accomplished.  The  unintentional  discrimination  in  favor  of  small 
seeds  and  small  bolls  would  be  avoided.  The  lint  index  would  give 
the  breeder  a  far  better  assurance  of  superiority  than  the  percentage 
cou hi  ever  afford.  Reducing  the  size  or  weighl  of  the  seed  would  no 
t  give  a  variety  the  misleading  advantage  that  it  does  by 
Increasing  the  lint  percentage.  The  chances  are  fair  that  the  largest 
amounts  of  lint  will  be  found  on  seeds  of  large  size,  if  not  on  the 
largest.  At  the  same  time  large  seeds  would  not  he  admitted  if  the 
amount   of  lint    were  small. 

The  relation  between  large  seeds  and  large  amounts  of  lint  (high 
lint  index'  has  been  toted  h\  Mr.  I ).  X .  Shoemaker,  of  the  Bureau 
of  Plant  Industry,  by  a  study  of  weights  of  seeds  and  lint  in  a  series 
of  selections  of  Triumph  cotton.  This  \ariet\  is  very  well  adapted 
for  such  study  because  it  represents  one  of  the  most  uniform  types 
of  I  [pland  cot  ton. 

The  weights  of  73  samples  were  used  for  comparison.  The  avei 
weight  of  Kit)  seeds  was  12.37  grams,  and  the  average  weight  of  lint 
of  inn  seeds  was  7.38  grams.  Of  II  plants  whose  lint  was  above  the 
average  only  4  plants  fell  below  the  average  in  weighl  of  seed.  Simi- 
larly, of  29  plants  which  fell  below  the  average  in  weight  of  lint  only 
4  were  above  the  average  in  weight  of  seed  and  these  exceeded  the 
average  only  a  little.  No  such  evidence  of  correlation  was  found 
when  the  same  data  were  arranged  with  reference  to  size  of  -ceil  and 
percentage  of  lint.  Of  the  28  plants  which  showed  lint  percentages 
above  the  average  of  :!7.7.  about  hal  lad  seeds  below  the  aver- 

weight,  while  the  other  13  had  seeds  above  the  avert) 

The  -election  of  the  plant  with  the  liighest  percentage  of  lint  i  t2.8) 
would  have  meant  the  rejection  of  no  less  than  II  plant-  whose  seeds 
produced  larger  amount-  of  lint.      In  other  words,  the  plant  with  the 

[Cir.ll] 


14  JUDGING    COTTON    VARIETIES   BY   LINT    PERCENTAGES- 

highest  percentage  would  have  ranked  as  number  42  in  the  series  of 
?:!  plants  if  arranged  by  lint  indexes.  The  plant  with  the  highest 
percentage  of  lint  really  had  only  seven-eighths  as  much  lint  on  its 
seeds  as  the  plant  that  showed  the  highest  lint  index.  Tins  serves  to 
indicate  the  extent  of  the  practical  difference  in  this  variety  between 
the  lint  index  and  the  lint  percentage  as  the  basis  of  selection.  If  all 
the  plants  were  like  that  with  the  largest  percentage  of  lint,  the  crop 
would  be  one-eighth  smaller  than  if  they  were  all  like  that  with  the 
highest  lint  index,  provided,  of  course,  that  both  produced  the  same 
numbers  of  seeds. 

The  only  objection  to  the  use  of  lint  indexes  instead  of  the  lint 
percentages  is  that, the  labor  of  determining  the  indexes  is  somewhat 
greater,  though  it  is  no  more  than  would  always  be  required  to  avoid 
the  danger  of  preferring  inferior  stocks  because  of  high  percentages. 
The  counting  and  weighing  of  100  seeds  after  ginning  is  a  simple 
matter.  The  additional  difficulty  would  come  in  counting  seeds 
while  the  lint  is  still  on  them,  and  then  in  ginning  these  small  quan- 
tities separately  and  at  the  same  time  with  sufficient  accuracy  to 
make  the  results  of  value. 

The  lint  percentage  affords  a  means  of  avoiding  this  difficulty  with- 
out lessening  the  accuracy  of  the  results,  for  the  weight  of  the  fiber 
of  100  seeds  can  easily  be  calculated  after  the  weight  of  the  seeds  and 
the  lint  percentage  are  known.  The  weight  of  the  hundred  seeds 
divided  by  the  percentage  of  seed  gives  the  weight  of  the  hundred 
seeds  before  ginning.  Subtracting  the  weight  of  the  ginned  seeds 
gives  the  lint  index  or  weight  of  the  lint  of  the  hundred  seeds.  With 
a  slide  rule  it  is  easier  to  multiply  the  weight  of  the  seed  by  the  lint 
percentage  and  then  divide  by  the  percentage  of  seed. 

The  lint  percentage  is  made  more  reliable  by  using  large  samples 
the  seeds  of  which  do  not  need  to  be  counted,  for  the  percentage  is  a 
matter  of  weight  alone.  Thus  the  percentage  still  remains  of  use  to 
the  breeder,  though  no  longer  employed  by  itself  as  a  standard  for 
judging  varieties.  The  index  has  a  direct  relation  to  the  size  of  the 
seed  which  the  percentage  alone  does  not  have. 

Lint  indexes  determined  in  this  way  can  be  still  further  corrected 
or  combined  with  the  results  of  other  tests  of  productiveness,  such 
as  the  amount  of  lint  from  10  bolls  or  the  amount  of  lint  yielded  by  a 
whole  plant.  Nevertheless,  there  is  not  tin1  same  need  of  such  cor- 
rections as  when  the  percentage  was  used  directly  as  a  standard. 
The  number  of  seeds  in  a  lock  of  cotton  appears  to  he  much  more 
constant  than  the  number  of  locks  in  a  boll,  so  that  10-boll  samples 
are  likely  to  be  much  more  subject  to  variation  than  the  lint  indexes 
unless  care  lie  taken  or  allowances  made  for  differences  in  the  number 
of  locks  and  in  the  number  of  seeds  in  the  locks. 

[Cir.   II  I 


.11  l",i.\ 1  i<>_\    VARIETIES    i:V    UN  I     PERCENTAGES. 


15 


The  following  table  illustrates  the  range  of  diversitj  of  linl  indexes 
and  percentages  in  differenl  varieties  and  types  of  cotton.  The  lasl 
two  columns  shov  the  differences  of  rank  which  resull  from  tlu>, 
substitution  of  the  lint  index  for  the  lint  percentage. 

Tabli    I       /    am  pies  of  lint  indexes  of  different  varieties  of  cotton  compared  with  lint 

i  ntages. 


Weight 

Lint  index 

III  of 
lint  oflOO 
seeds  . 

Lint  per- 
cenl 

-  lo  of 
lint  to  seed 
cotton.) 

Hank  by 

Rank  by 

Rank  by 
age. 

Gram*. 

(iriimx. 

P(  r  ct  nl. 

11.33 

1 

1 

(I 

- 

9.  14 

7 

2 

2 

13.  12 

- 

• 

8 

3 

4 

13.97 

8.00 

6 

4 

7 

10.00 

7.50 

12  3 

14 

5 

1 

11.26 

7.28 

39.  3 

13 

6 

3 

i     i 

33. 7 

5 

7 

10 

U.62 

12 

8 

8 

16.  in 

• 

3 

9 

15 

18.20 

5.43 

23  o 

2 

10 

17 

• 

.-.  17 

• 

19 

11 

11.58 

5.13 

11 

12 

11 

4.90 

15 

13 

11 

4.  16 

35.  3 

20 

14 

9 

14  62 

4 

15 

is 

• 

30.8 

17 

16 

13 

i 

31.5 

is 

17 

12 

21.3 

9 

is 

19 

U  5 

16 

19 

16 

12.53 

15.1 

10 

20 

23 

1.39 

18  6 

21 

21 

0 

1.11 

is  3 

22 

22 

21 

.81 

16.  1 

23 

23 

22 

CONCLUSIONS. 

The  currenl  opinion  thai  a  biigher  percentage  of  lint  proves  the 
superiority  of  a  variety  of  cotton  is  a  dangerous  error,  more  likeh  to 
load  to  the  deterioration  of  cotton  varieties  than  to  improvement. 
High  lint  percentages  give  no  assurance  of  large  yields  or  of  bigh 
quality,  but  ma\  resull  from  smaller  or  lighter  seeds  and -may  char- 
acterize weak  or  unproductive  varieties.  Other  features  which  bring 
increased  productiveness  or  bigher  quality  may  more  than  compen- 
sate for  lower  linl  percentages  and  should  have  the  impartial  consid- 
eral  ion  of  the  farmer  and  breeder. 

The  fact  that  linl  percentages  are  used  by  buyers  to  estimate  the 
amount  of  lint  in  a  crop  of  cotton  affords  no  reason  why  the  farmer 
or  the  breeder  should  consider  the  lint  percentage  as  the  chief  require- 
ment. The  custom  of  selling  cotton  by  percentage  of  lint  should  not 
establish  in  the  mind  of  the  farmer  the  idea  thai  the  lint  percentage 
is  a  true  standard  forjudging  varieties  for  planting.  The  agricultural 
question  of  how  to  produce  the  most  fiber  to  the  acre  is  entireh  sepa- 
rate from  the  commercial  question  of  calculating  the  amount  ol  lint 
in  the  crop  after  the  seed  cotton  bas  been  harvested. 

I  fir.    11  | 


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16  JUDGING   COTTON   VARIETIES   BY   LINT    PERCENTAGES. 

The  farmer  and  the  breeder  must  consider  the  lint  percentages  in 

relation  to  other  factors  of  practical  importance.  The  size  and  vigor 
of  the  seeds  must  be  taken  into  account,  as  well  as  the  fertility  of  the 
variety  and  the  length  and  quality  of  the  fiber.  It  is  only  when  these 
other  qualities  are  maintained  that  higher  lint  percentages  can  be 
accepted  as  evidence  of  the  superiority  of  a  variety  or  specially 
selected  strain  of  cotton. 

Superiority  in  the  one  factor  of  lint  percentage  must  not  be  pur- 
chased at  the  expense  of  quality,  productiveness,  or  early  maturity. 
It  would  not  be  wise  to  select  for  any  of  these  factors  alone  and 
neglect  the  others,  nor  is  it  wise  to  select  by  lint  percentages  alone. 
Persistent  narrow  selection  directed  to  any  one  feature  like  the  per- 
centage of  lint  would  be  more  likely  to  injure  than  to  benefit  a 
variety,  however  much  the  variety  may  appear  to  improve  as  long 
as  the  lint  percentage  is  accepted  as  the  sole  standard  of  excellence. 

On  the  other  hand,  it  need  not  be  supposed  that  lint  percentages 
arc  of  no  value  because  they  are  not  as  significant  as  often  supposed. 
Though  not  a  question  of  primary  importance,  like  quality  and  yield, 
the  lint  percentage  is  one  of  the  factors  of  fertility  which  should  not 
be  left  out  of  account.  Individual  cotton  plants  of  the  same  variety 
may  be  expected  to  differ  as  much  in  percentages  of  lint  as  in  other 
respects,  and  there  is  every  reason  to  suppose  that  larger  yields  can 
be  obtained  by  selection  for  higher  percentages  of  lint  if  other  factors 
of  fertility  and  value  are  not  left  out  of  account.  The  safest  and 
most  effective  way  of  using  lint  percentages  for  agricultural  and 
breeding  purposes  is  for  determining  a  lint  index,  representing  the 
amount  of  lint  produced  by  100  seeds.  Such  indexes  afford  much 
more  reliable  standards  for  judging  varieties  than  the  lint  percentages 
used  alone. 

Without  going  to  the  other  extreme  of  attempting  to  develop  low- 
percentage  varieties,  farmers  and  breeders  should  avoid  limiting  selec- 
tion to  individuals  or  to  varieties  with  high  percentages  unless  they 
have  carefully  assured  themselves  that  the  other  desirable  qualities, 
such  as  large  seeds  and  large  bolls,  are  not  declining.  Other  things 
being  equal,  a  decline  in  these  features  would  he  more  likely  than  an 
improvement  if  selection  were  limited  to  the  one  feature  of  lint 
percentages. 

Approved : 

James  Wilson, 

Secretary  of  Agricultun . 

Washington,  I).  O,  Jura  28,  1008. 

[Cir.  11] 


